Freedom has two components: Positive Freedom and Negative Freedom. Negative Freedom is a lack of restriction from doing something, while Positive Freedom is the ability to do something. For example, I am free to go to Mars through the lens of Negative Freedom but not through the lens of Positive Freedom.
Restricting Negative Freedom can enhance Positive Freedom. If a terrorist hate group is not allowed to exist, then those who would have been their victims can be free to live their lives without having them cut short by this disallowed association. This is a pro-freedom move in the direction of greater fairness and safety in Germany.